2013 Fiscal Year Final Research Report
Study of rock anelasticity for seismological application
| Project/Area Number |
23340127
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Solid earth and planetary physics
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
TAKEI Yasuko 東京大学, 地震研究所, 准教授 (30323653)
|
|---|
| Project Period (FY) |
2011-04-01 – 2014-03-31
|
| Keywords | 非弾性 / 地震波減衰 / 多結晶体 / 粒界滑り / アナログ物質 |
|---|
| Research Abstract |
Recent experimental studies have shown that anelasticity of polycrystalline materials is subject to the Maxwell frequency (fm) scaling: 1/Q(fn) with fn=f/fm. However, the applicability of this scaling to the seismic waves has not been guaranteed because fn in the laboratory is usually much lower than that of the seismic waves (6 < log_10(fn) < 9). By using polycrystalline organic borneol as an analogue to mantle rock, we measured anelasticity up to log_10(fn) = 8 and found that this scaling is not fully applicable at log_10(fn) > 4. A closer examination showed that each of the relaxation spectra obtained under various temperature, grain size, and chemical composition can be represented by the superposition of a background subject to the Maxwell frequency scaling and a peak centered at log_10(fn) ~ 3. Significant increases of the peak amplitude and width with increasing temperature, drain size, and impurity content result in failure of the Maxwell frequency scaling at log_10(fn) > 4.
|
